With the advent of multimedia communications, telecommunications and data communications have become increasingly complex. For example, multimedia communications applications such as real time transmission of digitally encoded video, voice, and other forms of data, may require new forms and systems for such data communications and telecommunications. One such new communications system is the CableComm system currently being developed by Motorola, Inc. In the CableComm system, a hybrid optical fiber and coaxial cable ("HFC") is utilized to provide substantial bandwidth over existing cable lines to secondary stations or devices such as individual, subscriber access units connected to one or more telephones, videophones, and/or a personal computers, workstations, other data terminal equipment ("DTE"), for example, in households having new or preexisting cable television capability. These coaxial cables are further connected via fiber optical cables to a central location having centralized, primary (or "head end") controllers or stations having receiving and transmitting capability. Such primary equipment may be connected to any variety of networks or other information sources, from the Internet, various on line services, telephone networks, to video/movie subscriber services. With the CableComm system, digital data, voice, video, and other multimedia data may be transmitted both in the downstream direction, from the primary station or controller (connected to a network) to the secondary station of an individual user (subscriber access unit), and in the upstream direction, from the secondary station to the primary station (and to a network). As discussed in greater detail below, the topology of such a communications system may be described as having a primary node (such as one formed by a primary station), connected via an intermediate network to many secondary nodes (such as those formed by secondary stations), which are then connected to corresponding terminals (forming a secondary network).
Such current systems have typically evolved to have separate voice telecommunications systems and separate data communications systems over the same HFC or other cable network. For example, in the CableComm system, separate and distinct secondary stations and primary stations are utilized for voice telecommunications through a circuit switched telecommunications network such as the public switched telephone network ("PSTN"), and separate and distinct secondary stations and primary stations are utilized for data communications through packet-based (or packet switched) communications networks, such as Internet Protocol ("IP") networks. Such separate systems have evolved because, for example, the dedicated bandwidth of circuit switched systems is typically preferable for time or delay sensitive applications, such as in real time voice and video communications in which any time delay is noticeable and may be a source of user irritation. Conversely, such dedicated bandwidth for real time communications may be inefficient for many data applications, such as electronic mail, in which such time delay may be immaterial. As a consequence, data communications systems have typically provided for asynchronous and often bursty data communications over a shared, non-dedicated bandwidth medium, such as an Ethernet or other packet-based system.
While such separate circuit switched and packet-based systems may be very efficient and effective for their separate purposes, other inefficiencies are introduced through, for example, duplication of the equipment and devices required for establishing, operating and maintaining separate systems. Such duplicative equipment typically has also been proprietary, with equipment designed for one system unable to communicate over another system. Accordingly, a need has remained for a unified circuit switched and packet-based communications system architecture, which may avoid duplication of equipment, but which nonetheless provides for efficient multimedia communications such as voice, video, and data communications. In addition, such a system architecture should also provide interworking between disparate systems, such that standardized and non-proprietary equipment may also be utilized.